Pattern forming method and pattern forming apparatus in which a substrate and a mold are aligned in an in-plane direction

ABSTRACT

A pattern forming method for forming an imprinted pattern on a coating material disposed on a substrate with a pattern provided to a mold. The method includes preparing a mold provided with a first surface including a pattern area, a second surface located opposite from the first surface, and an alignment mark provided at a position at which the alignment mark is away from the first surface, contacting the pattern area of the mold with the coating material disposed on the substrate, obtaining information about positions of the mold and the substrate by using the alignment mark and a mark provided to the substrate in a state in which the coating material is disposed on the substrate at a portion where the alignment mark and the substrate are opposite to each other, and effecting alignment of the substrate with the mold in an in-plane direction of the pattern area, on the basis of the information in a state in which the pattern area and the coating material contact each other.

This application is a divisional application of copending U.S. patentapplication Ser. No. 11/448,009, filed on Jun. 7, 2006.

This application also claims priority from Japanese Patent ApplicationsNo. 2005-168842, filed Jun. 8, 2005, No. 2005-302225, filed Oct. 17,2005, No. 2005-302703, filed Oct. 18, 2005, and No. 2006-137319, filedMay 17, 2006, which are hereby incorporated by reference herein.

FIELD OF THE INVENTION AND RELATED ART

The present invention relates to a mold, a pattern forming method, and apattern forming apparatus, which are used for forming a pattern. Morespecifically, the present invention relates to technology for aligning amold with a substrate.

In recent years, fine processing technology for transferring a minutepattern structure on a mold onto a member, such as a resin or a metal,has been developed. This technology is called nanoimprint ornanoembossing, and is expected to realize a resolution on the order ofseveral nanometers, so that it has received attention as next-generationsemiconductor fabrication technology in place of a light exposureapparatus, such as a stepper or a scanner. Further, according to thenanoimprint, a space structure can be formed on a wafer as a whole,although it varies depending on a size of the wafer, so that thenanoimprint technology has been expected to be applied to a wide varietyof fields of production technologies of optical devices, such asphotonic crystals and biochips, such as μ-TAS (Micro Total AnalysisSystem).

A case when processing by the nanoimprint is applied to semiconductorproduction has been described in Stephan Y. Chou et al., Appl. Phys.Lett. Vol. 67, Issue 21, pages 3114-3116 (1995). More specifically, on awork or workpiece (a semiconductor wafer in this case), a layer ofphotocurable resin is formed. Then, a mold having a desired unevenpattern is pressed against the resin, followed by irradiation with lightunder pressure to cure the resin. As a result of curing of the layer ofthe photocurable resin, the uneven pattern of the mold is transferredonto the work. When etching, or the like, is effected with the curedresin layer as a mask, pattern formation on the semiconductor wafer canbe realized.

In the imprint technology, it is necessary to precisely effect(positional) alignment of the mold with the work during the patterntransfer.

The alignment is generally effected by optically reading an alignmentstructure (hereinafter also referred to as an alignment mark) providedto the mold and an alignment mark provided to the work, such as thesemiconductor wafer, from the mold side.

However, in the case wherein a resin onto which a pattern of the mold istransferred is interposed between the mold and the work, the followingproblem can be caused to occur.

More specifically, the resin is caused to contact the alignment mark onthe mold side, whereby the alignment mark is unclearly observed in somecases. Further, in the case wherein a difference in a refractive indexbetween the mold and the resin is insufficient, the alignment mark isparticularly less visible.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a mold capable of beingapplied to high accuracy alignment.

Another object of the present invention is to provide a pattern formingmethod using the mold and a pattern forming apparatus for effecting suchpattern formation.

One aspect of the present invention is to provide a mold, comprising:

a first surface having an area of a pattern to be transferred;

a second surface located opposite from the first surface; and

an alignment mark embedded in the mold so as not to be exposed on thefirst surface and the second surface.

Another aspect of the present invention is to provide a mold,comprising:

a first surface having an area of a pattern to be transferred;

a second surface located opposite from the first surface;

a first mark provided at the first surface; and

a second mark for alignment provided at a position at which the secondmark is away from the first surface.

Yet another aspect of the present invention is to provide a patternforming method for forming an imprinted pattern on a coating materialdisposed on a substrate with a pattern provided to a mold, comprising:

preparing a mold provided with a first surface including a pattern area,a second surface located opposite from the first surface, and analignment mark provided at a position at which the alignment mark isaway from the first surface;

contacting the pattern area of the mold with the coating materialdisposed on the substrate;

obtaining information about positions of the mold and the substrate byusing the alignment mark and a mark provided to the substrate in a statein which the coating material is disposed on the substrate at a portionwhere the alignment mark and the substrate are opposite to each other;and

effecting alignment of the substrate with the mold in an in-planedirection of the pattern area on the basis of the information in a statein which the pattern area and the coating material contact each other.

Still another aspect of the present invention is to provide a patternforming method for forming a pattern on a member, to be processed, byusing a pattern provided to a mold, comprising:

preparing a mold provided with a first surface including a pattern area,a second surface located opposite from the first surface, a first markprovided at the first surface, and a second mark for alignment providedat a position at which the alignment mark is away from the firstsurface; and

effecting alignment of the mold with the member to be processed by usingthe second mark of the mold and a third mark for alignment provided tothe member to be processed.

Yet another aspect of the present invention is to provide a patternforming method for forming a pattern on a member, to be processed, byusing a pattern provided to a mold, comprising:

effecting alignment of the mold with the member to be processed in anin-plane direction of a pattern area of the mold by using firstpositional information about a relative positional relationship betweena first mark provided at a surface of the mold at the same level as apattern area formed surface of the mold and a second mark located awayfrom the pattern area formed surface and using second positionalinformation about a relative positional relationship between the secondmark and a third mark provided to the member to be processed.

According to another aspect of the present invention, there is provideda pattern forming apparatus for performing any one of the patternforming methods described above, comprising:

a mold holding portion for holding a mold; and

a substrate supporting portion for supporting a substrate,

wherein the mold holding portion and the substrate supporting portionare configured to be moved relative to each other in an in-planedirection.

Yet another aspect of the present invention is to provide a patterntransfer apparatus, comprising:

an alignment mechanism for effecting alignment of a mold with a memberto be processed, the alignment mechanism being configured to effectalignment of the mold with the member to be processed in an in-planedirection of a pattern area of the mold by using first positionalinformation about a relative positional relationship between a firstmark provided at a surface of the mold at the same level as a patternarea formed surface of the mold and a second mark located away from thepattern area-formed surface and using second positional informationabout a relative positional relationship between the second mark and athird mark provided to the member to be processed.

Further, the present invention provides the following molds, processingapparatuses, processing methods, and mold production methods.

More specifically, there is provided a mold having a processing surfaceat which a pattern is formed and characterized in that it is providedwith an alignment structure which is retracted from the processingsurface by several micrometers to several millimeters.

In another aspect of the present invention, the mold having the patternis characterized in that it is provided with an apparatus structure inan area between the processing surface and a surface opposite from theprocessing surface.

In another aspect of the present invention, the mold having the patternis characterized in that it is provided with an apparatus structure at asurface opposite from the processing surface.

There is also provided a processing apparatus capable of a mold with awork in a planar direction parallel to a processing surface of the moldwhen the mold is pressed against the work to transfer a pattern formedon the mold onto the work. More specifically, the processing apparatusincludes a mechanism for effecting alignment in a state in which themold is caused to contact the work. In this case, the apparatus furtherincludes a positional deviation detection mechanism for detectingpositional deviation by contact the mold with the work and a mechanismfor comparing a detected value of positional deviation with apredetermined value. The apparatus may further include a mechanism formoving the mold away from the contact position toward the processingsurface of the mold when positional deviation having a value not lessthan the predetermined value is detected by the positional deviationdetection mechanism.

According to the present invention, there is further provided aprocessing method including a step shown below during transfer of apattern formed on the mold onto the work by pressing the mold againstthe work. More specifically, the processing method is characterized inthat in the case when the processing is performed while effectingalignment of the mold with the work in an in-plane direction parallel tothe processing surface of the mold, such a step of effecting alignmentof the mold with the work by using the above described mold as the moldis performed.

More specifically, the apparatus of the mold with the work in thein-plane direction parallel to the processing surface of the mold iseffected in the state of contact of the mold with the work through thefollowing steps (1) and (2):

(1) a positional deviation detection step of detecting positionaldeviation by contacting the mold with the work and a step of comparing adetected value with a predetermined value, and

(2) a step of moving the mold away from the contact position toward theprocessing surface of the mold when positional deviation having a valuenot less than the predetermined value is detected in the positionaldeviation detection step.

The present invention further provides a process for producing a moldhaving a pattern, to be transferred, at a processing surface thereof.

The mold production process is characterized by including at least oneof the following steps (3) to (6):

(3) a step of providing an alignment structure in the mold at a positionaway from the processing surface of the mold by several micrometers toseveral millimeters,

(4) a step of providing the alignment structure in the mold in an areabetween the processing surface of the mold and a surface opposite fromthe processing surface,

(5) a step of providing the alignment structure to the mold at thesurface opposite from the processing surface of the mold, and

(6) a step of providing the alignment structure and forming the patternat the processing surface simultaneously in the same process. In thiscase, a mask layer for forming the alignment structure and a mask layerfor forming the pattern at the processing surface may preferably be inthe same plane.

The present invention further provides a pressure processing apparatusfor pressing either one of a mold and a member to be processed(hereinafter also referred to as a processing member) to transfer apattern formed at a processing surface of the mold onto the processingmember.

This apparatus is characterized by an alignment mechanism constituted inthe following manner.

More specifically, the alignment mechanism is constituted so that itdetects a first relative position between a mark provided at theprocessing surface of the mold and a mark provided at a position apartfrom the processing surface toward an inner portion of the mold and asecond relative position between the mark provided at the position apartfrom the processing surface toward the inner portion of the mold and amark provided with respect to the processing member, and compares thesefirst and second relative positions with each other to effect alignmentof the mold with the processing member.

The alignment mechanism is characterized by including a means forstoring a result of measurement of the first relative position and ameans for storing a result of measurement of the second relativeposition. The alignment mechanism further includes an optical system forguiding light from a light source to a portion between the mark providedat the position apart from the processing surface of the mold and themark provided at the processing surface of the mold. The optical systemis also configured to guide the light from the light source to a portionbetween the mark provided at the position apart from the processingsurface of the mold and the mark provided with respect to the processingmember. The optical system can also be configured to have a referencealignment mark.

The present invention further provides a pressure processing method ofpressing either one of a mold and a processing member to transfer apattern formed at a processing surface of the mold onto the processingmember.

More specifically, the pressure processing method is constituted so thatit detects a first relative position between a mark provided at theprocessing surface of the mold and a mark provided at a position apartfrom the processing surface toward an inner portion of the mold and asecond relative position between the mark provided at the position apartfrom the processing surface toward the inner portion of the mold and amark provided with respect to the processing member, and includes analignment step of comparing these first and second relative positionswith each other to effect alignment of the mold with the processingmember.

The alignment step can include the following steps (1), (2) and (3):

(1) a step of measuring and storing a first error as a horizontal androtational error of the mark provided at the processing surface of themold on the basis of the mark provided at the position away from theprocessing surface of the mold,

(2) a step of measuring and storing a second error as a horizontal androtational error of the mark provided with respect to the processingmember on the basis of the mark provided at the position away from theprocessing surface of the mold, and

(3) a step of moving the processing member horizontally and rotationallyso that the first error and the second error are in agreement with eachother.

Further, the alignment step may include a step of measuring the firsterror and the second error by using an optical system having a referencealignment mark.

The present invention further provides a mold, for pressure processing,characterized by having a second mark apart inwardly from a horizontalposition of a processing surface of a mold on which a pattern is formed,and a first mark formed at a surface at the same level as the processingsurface of the mold. The second mark includes a first positionmeasurement mark and an alignment mark corresponding to the markprovided with respect to the processing member, and the first markincludes a second measurement mark corresponding to the firstmeasurement mark. The second mark is provided at a surface opposite fromthe processing surface of the mold and can be constituted by thepresence or absence of a transparent member constituting the mold or adifference in density of the transparent member. Further, the secondmark may also be constituted so that it is provided in a secondtransparent member, constituting the surface opposite from theprocessing surface of the mold, different in composition from a firsttransparent member constituting the processing surface of the mold.Further, the second mark may further be constituted so that it isprovided at the surface opposite from the processing surface of the moldby embedding a second member, different in composition from the abovedescribed transparent member, in a portion at which the transparentmember constituting the mold is not present. The second mark may furtherbe constituted by a mark which is provided at the surface opposite fromthe processing surface of the mold and is protruded from the transparentmember constituting the mold at the opposite surface.

The present invention further provides a process for producing a moldfor pressure processing, wherein a pattern formed at a processingsurface of a substrate is transferred onto a resinous layer provided ata surface of a substrate constituting a processing member. Thisproduction process is characterized by including the following steps (1)and (2):

(1) a step of forming a second mark at a position inwardly away from aprocessing surface of the substrate, and

(2) a step of forming a processing pattern and a first mark, afterforming the second mark, at a processing surface located opposite from asurface of the substrate on which the second mark is formed, on thebasis of a part of the second mark.

The present invention further provides another process for producing amold for pressure processing, wherein a pattern formed at a processingsurface of a substrate is transferred onto a resinous layer provided ata surface of a substrate constituting a processing member. Thisproduction process is characterized by including the following steps (3)and (4):

(3) a step of forming a second mark at a position inwardly away from aprocessing surface of the substrate and forming a first mark, afterforming the second mark, at a processing surface located opposite from asurface of the substrate on which the second mark is formed, byirradiation with short pulse laser light from the outside of one surfaceof the substrate, and

(4) a step of forming a processing pattern at the processing surface onthe basis of the part of the second mark.

The mold used in the present invention includes a mold having a patternarea at a surface thereof, e.g., a surface uneven (projection andrecess) pattern to be imprinted. The mold is also herein referred to asa template in some cases.

The processing member (member to be processed or a work) means anarticle, including a portion onto which a pattern of the mold is to betransferred, such as a substrate itself or a substrate having thereon acoating material. The coating material on the substrate may be formed ina continuous film or a discontinuous film such as a dot-like filmportion. Details thereof will be described later. As the substrate, itis possible to use a flat plate-like member, such as a silicon wafer orquartz wafer, but the present invention is not limited thereto, so longas a member can be used for carrying out the present invention.

According to the above-described constitutions, it is possible toprovide a mold capable of being applied to alignment of the mold with aprocessing member (work) with high accuracy. It is also possible toprovide a pattern forming method using the mold, and a pattern formingapparatus and a pattern transfer apparatus, which are used forpermitting the pattern formation.

These and other objects, features and advantages of the presentinvention will become more apparent upon a consideration of thefollowing description of the preferred embodiments of the presentinvention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1, 2A to 2D, and 3A to 3D are schematic sectional views eachshowing a mold according to the present invention.

FIG. 4 is a schematic diagram showing an example of a constitution of aprocessing apparatus in an embodiment of the present invention.

FIGS. 5A and 5B are flow charts each showing a processing method in anembodiment of the present invention.

FIG. 6 is a schematic view for illustrating a mechanism of an occurrenceof relative positional deviation during imprinting.

FIGS. 7A and 7B are schematic views for illustrating a mechanism ofdamage to a mold and a wafer during imprinting.

FIG. 8 is a schematic view for illustrating a mechanism of an occurrenceof error factors in a detection system during imprinting.

FIGS. 9A to 9E are schematic views for illustrating an imprint processin an embodiment of the present invention.

FIG. 10 is a schematic view showing an example of an alignment structureincluding a periodic structure in an Embodiment of the presentinvention.

FIGS. 11A and 11B are schematic views each showing an example of analignment structure using a periodic structure in an Embodiment of thepresent invention.

FIGS. 12A to 12H, 13A to 13I, 14A to 14E, and 15A and 15E are schematicviews respectively showing a process for producing a mold according toan embodiment of the present invention.

FIGS. 16A and 16B are schematic views each showing an example of anarrangement of an alignment structure in an embodiment of the presentinvention.

FIGS. 17A and 17B, and 18A and 18B, are views and flow charts eachshowing a pattern forming method according to an embodiment of thepresent invention.

FIGS. 19A to 19C and 20A to 20E are schematic views each showing aconstitutional example of a mold in an Embodiment of the presentinvention.

FIGS. 21A to 21G are schematic views showing steps of a process forproducing a mold according to an Embodiment of the present invention,wherein a front surface and a back surface of the mold are changed toprepare the mold.

FIG. 22 is a schematic view showing a constitution of a pressureprocessing apparatus in an Embodiment of the present invention.

FIGS. 23A and 23B are schematic views for illustrating a constitution ofan optical system using a reference mark in a pressure processingapparatus in an Embodiment of the present invention.

FIGS. 24A to 24E are schematic views showing steps of a process forproducing a mold according to an Embodiment of the present invention,wherein the mold is processed from one side thereof.

FIG. 25 is a schematic view for illustrating a constitutional example ofan apparatus according to an Embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment Mold1

A mold according to this embodiment will be described with reference toFIG. 1.

Referring to FIG. 1, a mold 1100 has a first surface 1050, a secondsurface 1060 located opposite from the first surface 1050, a patternarea 1000 formed at the first surface 1050, and a mark for alignment(alignment mark) 1070 embedded in the mold 1100 so as not to be exposedto the first surface 1050 and the second surface 1060.

A material for constituting the mold 1100 and a material forconstituting the alignment mark 1070 and different from each other, thusproviding a difference in refractive index therebetween. The differencein refractive index may preferably be, e.g., not less than 0.1 whenoptical reading of the alignment mark 1070 is taken into consideration.The material for the alignment mark 1070 is not particularly limited, solong as it can ensure the difference in refractive index with the mold1100 and can be optically read. For example, the alignment mark 1070 maybe constituted by a pore which is in vacuum or filled with gas, such asair or nitrogen.

In this embodiment, it is important that the alignment mark 1070 isembedded in the mold 1100. By such a constitution, during imprinting, itis possible to obviate such a problem that the alignment mark is lessread optically due to a resinous layer interposed between a substrateand the mold. Such a problem arises in the case when residue of theresin attaches to the alignment mark or in the case when the differencein refractive index between the mold and the resin is insufficient. Inthe pattern area 1000, an uneven pattern is formed at the first surface1050 of the mold 1100. The uneven pattern may also be formed byproviding a projection portion on a flat first surface 1050 and then maybe transferred onto the substrate.

In the case when the pattern area 1000 and the alignment mark 1070 areread by a single optical system, the alignment mark 1070 may preferablybe disposed closer to the first surface 1050 than the second surface1060 from a viewpoint such that it is possible to adjust focus on boththe pattern area 1000 and the alignment mark 1070 simultaneously.

Incidentally, as shown in FIG. 2C, the alignment mark 1070 can also beembedded in a material 107 different from the material for the mold1100.

Further, the alignment mark can be prepared at the same surface as thefirst surface 1050 and covered with a protective layer so as not to beexposed outside of the mold. In this case, a material for the protectivelayer may be identical to the material for the mold, but may be selectedas a material having a different refractive index from the moldmaterial. Incidentally, the state in which the alignment mark is notexposed outwardly means that the alignment mark does not directlycontact the resin interposed between the mold and the substrate.

In the case of imprinting using a photocurable resin, the mold isconstituted by a light transmissive substance such as quartz, pyrex(registered trademark), or sapphire. In the case when it is notnecessary to transmit light through the mold, a metallic material or Sican also be used as the material for the mold.

Hereinbelow, a production process of the mold in which the alignmentmark is embedded, as shown in FIG. 1, will be described later withreference to FIGS. 13A to 13E and FIG. 14.

From a viewpoint of prevention of attachment of the resin to thealignment mark of the mold during transfer of the uneven pattern of themold, while interposing the resin between the substrate and the mold,the alignment mark (alignment structure) may also be constituted in thefollowing manner

For example, as shown in FIGS. 2A to 2D, such an alignment structurechange in optical characteristic, with respect to an in-plane directionat the surface of the pattern area of the mold, is constituted. In thesefigures, 101 represents a processing surface, 102 represents analignment structure surface, 103 represents a distance A, 104 representsa mold, 105 represents a mold for a pattern (first member), 106represents a mold for alignment (second member), and 107 represents alight-transmissive substance.

FIG. 2A shows an embodiment of such a constitution that the alignmentstructure surface 102 is disposed at a position inwardly away from theprocessing surface 101 with a certain distance A 103. At this position,the resin does not contact the alignment structure surface 102. Thedistance A may preferably be set from several micrometers to severalmillimeters, depending on a focus depth of a microscope.

FIG. 2B shows an embodiment of such a constitution that the first member105, on which an uneven pattern for transfer is formed and the secondmember 106 on which the alignment structure 102 is formed, are appliedto each other, so that it is possible to easily obtain a constitutionthat the alignment structure is located away from the uneven pattern.

FIG. 2C shows an embodiment of such a constitution that the alignmentstructure is embedded in the light-transmissive substance as describedabove more specifically, and FIG. 2D shows an embodiment of such aconstitution that the alignment structure is formed at the surfaceopposite from the processing surface.

According to a study by the present inventors, in the case when thealignment structure is formed on the same surface side as the processingsurface, as shown in FIGS. 2A and 2B, it has been found that thealignment structure may preferably be several microns to severalmillimeters away from the processing surface toward the oppositesurface.

Generally, the resin on the substrate to be processed is coated in athickness of 1 μm or below, but in consideration of a possibility thatthe resin is increased in height by pressure application, it isdesirable that the resin be located away from the level of theprocessing surface by several micrometers or above. Further, an accuracyof the mold in terms of structural design is lowered when the distancebetween the processing surface and the alignment structure is too large,so that the distance may desirably be not more than several millimeters.Herein, the term “several micrometers” means, e.g., 2-3 μm and the term“several millimeters” means, e.g., 2-3 mm. The distance is not limitedto these ranges in the case when the alignment structure is located atthe surface opposite from the processing surface of the mold or at aninner portion of the mold constituting member.

The alignment structure may be constituted in a shape of, e.g., a box, across, or a bar, or as a periodic structure, or a combination of these.

Next, an embodiment of the production process of the mold shown in FIGS.2A to 2D is described with reference to FIGS. 12A-15E.

(A) Production Process of Mold of FIG. 2A (FIGS. 12A-12H)

(1) A hard mask layer 1201 is formed on a mold substrate 104 (FIG. 12A).

(2) A mask layer 1204 is formed on the hard mask layer 1201, followed byetching of the hard mask layer 1201 (FIG. 12B). Patterning of the masklayer 1204 may, e.g., be effected by light exposure with a stepper or ascanner, or irradiation with an electron beam. In FIG. 12B, 1202represents an area in which an alignment structure is formed and 1203represents an area in which an actual pattern is formed.

(3) The mold substrate 104 is etched in a desired depth by using, as amask, the hard mask layer 1201 or a combination of the hard mask layer1201 with a residual film of the mask layer 1204 (FIG. 12C). In thiscase, the desired depth means a depth required for imprinting. Afterthis step, in the case where the mask layer 1204 remains, it is removedby a treatment such as aching, etc.

(4) A surface of the mold in an area other than the alignment structurearea 1202 is coated with a mask layer 1205 (FIG. 12D).

(5) The mold substrate 104 is etched in a desired depth with the hardmask layer 1201 as a mask (FIG. 12E). In this case, the desired depthmeans a depth which is deeper than the distance A 103 between thealignment structure surface 102 and the processing surface 101 byseveral tens of nm to several micrometers.

(6) The hard mask layer 1201 is etched by using the mask layer 1205 asthe mask and the mold substrate 104 is then continuously etched in thedepth corresponding to the distance A 103. The resultant etching surfaceconstitutes the alignment structure 102 (FIG. 12F).

(7) The mask layer 1205 is removed (FIG. 12G).

(8) The hard mask layer 1201 is removed (FIG. 12H). In this case,however, when the hard mask layer 1201 is formed of a light-transmissivesubstance, it is not necessarily removed in this step.

(B) Production Process of Mold of FIG. 2B (FIGS. 13A-13I)

(1) On a mold substrate 106, a light transmissive substance 1301 isformed in a film (FIG. 13A). The substance 1301 may desirably bedifferent from a material for the mold substrate 106 so as to ensureselectivity of etching. For example, the light-transmissive substancemay be constituted by SiN, TiO₂ or Al₂O₃, and the mold substrate 106 maybe constituted by SiO₂, CaF₂ or ITO (indium tin oxide).

(2) On the film 1301 of the light-transmissive substance, a layer 105 ofanother light-transmissive substance is formed (FIG. 13B). The substancefor the layer 105 may be identical to the material for the moldsubstrate 106.

(3) On the layer 105, a hard mask layer 1201 is formed of a lighttransmissive substance such as SiN, TiO₂ or Al₂O₃, a metallic material,such as Cr, WSi, or Al; Si, or the like (FIG. 13C).

(4) A mask layer 1204 is formed on the hard mask layer 1201, followed byetching of the hard mask layer 1201 (FIG. 13D). Patterning of the masklayer 1204 may, e.g., be effected by light exposure with a stepper or ascanner, or irradiation with an electron beam. A material for the masklayer 1204 may, e.g., be selected from an ordinary resist material usedfor photolithography, electron lithography, etc. In FIG. 13B, 1202represents an alignment structure area and 1203 represents an actualpattern area.

(5) The layer 105 of the light-transmissive substance is etched in adesired depth by using, as a mask, the hard mask layer 1201 or acombination of the hard mask layer 1201 with a residual film of the masklayer 1204 (FIG. 13E). In this case, the desired depth means a depthrequired for imprinting. After this step, in the case when the masklayer 1204 remains, it is removed by a treatment such as ashing, etc.

(6) A surface of the mold in an area other than the alignment structurearea 1202 is coated with a mask layer 1205, and the layer 105 oflight-transmissive substance is etched in a depth reaching the surfaceof the layer 1301 of the light-transmissive layer by using the hard masklayer 1201 as a mask (FIG. 13F). A material for the mask layer 1205 isselected from the ordinary resist material similar to the above step(4).

(7) A portion of the light transmissive substance layer 1301 exposed atthe bottom of the layer 105 by etching and the hard mask layer 1201 areetched. These etching processes may be performed separately, but mayalso be performed simultaneously in a common step in some cases.Thereafter, while using the mask layer 1205 as the mask, the layer 105is etched in a depth reaching the surface of the layer 1301 of thelight-transmissive substance (FIG. 13G).

(8) The mask layer 1205 is removed (FIG. 13H).

(9) The exposed layer 1301 and the hard mask layer 1201 are removed(FIG. 13I). However, when the hard mask layer 1201 is formed of a lighttransmissive substance, it is not necessarily removed. The distance A103 between the alignment structure surface 102 and the processingsurface 101 is determined by the thickness of the layer 105. Asdescribed above, the mold having the alignment mark 102 at a positiondisposed inwardly away from the pattern area 101 is realized.

(C) Production Process of Alignment Mark Embedded Mold of FIGS. 1 and 2(FIGS. 14A-14E)

(1) Similarly, as in the above process (B), the steps shown in FIGS. 13Ato 13E are performed.

(2) Similarly, as in the step shown in FIG. 13F, the layer 1301 exposedat the bottom of the light-transmissive substance layer 105 by etchingis etched by using the mask layer 1205 as the mask (FIG. 14A).

(3) At the entire mold surface, a layer 107 of a light-transmissivesubstance, such as SiO₂, inorganic SOG (Spin On Glass), or organic SOGis formed by spin coating, CVD, or the like (FIG. 14B). The layer 107 isformed so as to fill a recessed portion 1212 created by the etching inthe step (2).

(4) The light-transmissive layer 107 is removed to reach the surface ofthe mold substrate surface so as to leave a portion thereof filled inthe recessed portion 1212 (FIG. 14C). The mold substrate surface meansthe surface of the hard mask layer 1201 in the alignment structure area1202 and the surface of the mask layer 1205 in the remaining area, butthe former surface takes priority. The removal method may, e.g., beentire-surface etching back or CMP.

(5) The mask layer 1205 is removed (FIG. 14D). In the case when thelight-transmissive layer 107 still remains on the mask layer 1205, it isremoved a by lift-off method.

(6) The hard mask layer 1201 is removed (FIG. 14E), but it is notnecessarily required to be removed when the material for the hard masklayer 1201 is a light-transmissive substance. The distance A 103 betweenthe alignment structure surface 102 and the processing surface 101 isdetermined by the thickness of the layer 105. However, in this mold, thelight-transmissive substance layer 1301 is embedded in the layers 106,105, and 107, so that the layer 1301 is required to be well used incombination with these layers 105-107 in terms of optical contrast inorder to permit observation of the alignment structure.

(D) Production Process of Mold of FIG. 2D (FIGS. 15A-14E)

(1) On the surface of a mold substrate 104, a mask layer 1501 is formed(FIG. 15A). The mask layer 1501 may be formed as a resist or a hard maskand has an actual pattern area 1203 and a front/back positionalalignment structure area 1502. The mask layer 1501 is patterned by,e.g., light exposure with a stepper, a scanner, or the like, orirradiation with an electron beam.

(2) A mold substrate 104 is etched in a desired depth by using the masklayer 1501 (FIG. 15B). The desired depth in this case means a depthrequired for imprinting in the actual pattern area 1203.

(3) At a front surface, a protective layer 1503 of a resist, or thelike, is formed and, thereafter, at a back surface, a mask layer 1504 isformed (FIG. 15C). The mask layer 1504 has an alignment structure area1202 and a front/back alignment area 1505, which is optically alignedwith the front/back alignment structure area 1502 to adjust a positionalrelationship therebetween.

(4) The mold substrate 104 is etched in a desired depth by using themask layer 1504 (FIG. 15D). In this case, the desired depth may be anyvalue so long as the alignment structure can optically ensure aconstant.

(5) The resist 1503, the mask layer 1501, and the mask layer 1504 areremoved (FIG. 15E). When the mask layers 1501 and 1504 are formed of alight-transmissive substance, these layers are not necessarily requiredto be removed. The distance A 103 between the alignment structuresurface 102 and the processing surface 101 is determined by thethickness of the mold surface 104.

As described above, the mold having the first mark 1077 at the samesurface as the pattern area 1203 formed at the processing surface 101and the second mark 1201 for alignment at the surface opposite from thepattern area-formed surface is realized. Such a mold having two markswill be described more specifically in the Second Embodiment.

In the above description of the mold production process, particularly,the processes shown in FIGS. 12A to 14E have such an advantage thatpattern formation at the two different surfaces can be effected at onetime. With respect to a sample having a stepped portion, from arelationship of focal depth, it is difficult to obtain a sufficientresolution at both the surfaces in one operation. On the other hand, inthe case when pattern formation is effected two times, an error ofalignment is added, so that a relative distance between the two patternsis not ensured as designed. In the processes shown in FIGS. 12A-14E, oneoperation is only required, and it is possible to form the patterns atthe different two surfaces with the same resolution.

Second constitutional embodiments in this embodiment are describedabove, but the mold of the present invention is not limited thereto.Other molds are also embraced in the present invention, so long as theyhave an alignment structure changed in optical characteristic in anin-plane direction from a processing surface at which an uneven patternto be transferred onto a work to such an area that the resin does notcontact the mold.

In the case when alignment is actually effected with the above-describedmold, the alignment is effected by using the alignment structure of themold and the alignment structure formed on the work or a supportingtable of the work.

The above-described mold according to the present invention isapplicable to various types of imprinting, such as thermal imprinting,in which resin is thermally settled, but may, particularly, suitably beused for photoimprinting using a photocurable resin.

Second Embodiment Mold 2

A mold of this embodiment is characterized by including a first surfacehaving a pattern area for transfer, a second surface located oppositefrom the first substrate, a first mark provided at the first substrate,and a second mark provided at a position away from the first surfacetoward the second surface. The second mark is, e.g., the mark 102 shownin FIGS. 3A and 3B.

The mold will be described more specifically with reference to FIGS. 3Ato 3D.

In these figures, the same reference numerals as those in FIGS. 2A to 2Drepresent the same members or portions as those described in the FirstEmbodiment.

Referring to FIGS. 3A to 3D, a first mark 1077 is provided at the samesurface as a pattern area 101 having an unevenness (not shown). Thefirst surface is a surface at which the pattern area 101 is formed, andthe second surface is a surface 3101 opposite from the first surface.

The second mark is provided between the first and second surfaces or atthe second surface. In FIGS. 3A and 3B, the second mark is provided at aposition inwardly away from the first surface. The second mark may alsobe embedded in an area between the first and second surfaces, as shownin FIG. 3C, or at the second surface opposite from the patternarea-formed first surface, as shown in FIG. 3D.

For example, a mold having a first mark provided at the same surface asthe pattern area and a second mark for alignment at an opposite surfaceof the mark can be produced through the process shown in FIGS. 15A to15E described above. The mark 1077 shown in FIG. 15D is the first mark.

Further, as described in this embodiment, the mold having the first markat the same surface as the pattern area and the second mark at theopposite surface of the mold is shown in FIGS. 20A to 20E.

By providing the alignment mark at two positions, it is possible toeffect alignment with one of the alignment marks even in the case whenalignment with the other alignment mark is difficult.

Particularly, by providing the first mark (1077 shown in FIGS. 3A-3D) atthe same surface as the pattern area and the second mark at the positionaway from the first mark in the thickness direction of the mold 104, thefollowing effect is expected. More specifically, on the basis of thepattern area 101 (1000 shown in FIG. 3C), the second mark at the backsurface is different in position between a designed position and anactually prepared position in some cases. When this difference ispractically of no problem in an imprinting process, it is possible touse the mold described in the First Embodiment even when the differenceis caused to occur. However, in the case when it is necessary to performthe imprinting process in consideration of the difference, the mold ofthis embodiment is every effective. This is because, in this embodiment,the second mark is formed in a step other than the step of forming thepattern area, since the unevenness cannot be formed simultaneously atboth surfaces of the mold substrate. On the other hand, the first markcan be prepared in the same step as the pattern area, so that the firstmark can be formed at a position very close to the designed position. Inthe mold of this embodiment, it is possible to obtain a relativepositional relationship between the first mark and the second mark, sothat it is possible to obtain information as to whether the second markis formed with any error from the designed position with respect to thepattern area or the first mark. Incidentally, the material for the mold(template) may be the same material as those described in the FirstEmbodiment.

Third Embodiment Pattern Forming Method 1

A pattern forming method of this embodiment is performed in thefollowing manner.

First, a mold provided with a first surface including a pattern area, asecond surface located opposite from the first surface, and an alignmentmark provided at a position away from the first surface toward thesecond surface, is prepared. For example, the mold is shown in FIGS. 1to 3.

Then, the pattern area of the mold and a coating material (e.g., aphotocurable resin or resist) of a substrate are caused to contact eachother.

In FIG. 17A, 5000 represents the substrate, 3000 represents the coatingmaterial, and 104 represents the mold. Further, 1000 represents an areain which an uneven pattern to be transferred onto the coating materialis formed. In this figure, an actual unevenness of the uneven pattern1000 is not shown. An alignment mark 2070 is provided at a back surfaceof the mold 104 as a position away from the uneven pattern 1000. Theposition of the alignment mark 2070 in this embodiment is not limited tothe position at the back surface of the mold. The coating material 3000is applied onto the entire surface of the substrate 5000 or an arealarger than the pattern area of the mold. As a result, the mold 104 andthe substrate 5000 are placed in such a state that the coating material3000 is disposed at a portion 5050 (dotted circle) on the substrate 5000opposite to the alignment mark 2070. In this state, information aboutposition of the mold and the substrate (e.g., image information) isobtained by using the alignment mark and a mark provided on thesubstrate side.

Then, on the basis of this information, (positional) alignment of themold with the substrate in the in-plane direction of the pattern area iseffected. More specifically, the alignment marks 2070 and 5300 areoptically read by a single image pickup (sensor) device to effectalignment in the in-plane direction. In the pattern forming method ofthis embodiment, the alignment can be effected in such a state that thepattern area and the coating material are in contact with each other(contact state). In the present invention, the alignment of the moldwith the substrate may also be effected in a non-contact state.

In the case when a difference in refractive index between the mold andthe coating material is small, when the alignment mark of the mold islocated in the pattern area 1000, the alignment mark cannot be less readoptically or cannot be read optically due to the contact of the coatingmaterial with the mold. In the pattern forming method of thisembodiment, however, the alignment mark 2070 and the coating material3000 (e.g., resin or resist comprising a material curable by irradiationof light such as ultraviolet rays) are not in contact with each other.Accordingly, it is not necessary to strictly control a coating area ofthe coating material interposed between the mold and the substrate, sothat the coating material can also be prepared by spin coating. It isalso possible to form the coating material in the entire pattern area asa continuous film by providing a multiplicity of dot-like portions ofthe coating material by measures of a dispenser and decreasing adistance between the mold and the substrate.

The coating material is, e.g., photocurable resin and may preferably becured while effecting the alignment described above. This is becausepositional deviation is caused to occur in some cases in such a statethat the mold and the substrate indirectly contact each other via theresin. In other words, the coating resin may preferably be cured in sucha state that a gap between the substrate and the mold is controlledwhile effecting positional control in the in-plane direction. The curingof the coating material is effected by irradiating the coating materialwith, e.g., ultraviolet rays from the mold side. Examples of thephotocurable resin may include those of urethane-type, epoxy-type, andacrylic-type. It is also possible to use, as the coating material, athermosetting resin such as phenolic resin, epoxy resin, silicone resin,or polyimide, or a thermoplastic resin such as polymethyl methacrylate(PMMA), polycarbonate (PC), PET or acrylic resin. In this case, thepattern is formed by effecting heat treatment, as desired. As thecoating material, it is also possible to use polydimethylsiloxane(PDMS).

In this embodiment, it is also preferable that the following control iseffected.

More specifically, on the basis of the information obtained above,control of a distance (gap) between the substrate and the mold iseffected.

In some cases, positional deviation in the in-plane direction is causedto occur between the mold and the substrate when pressure is applied tothe resin interposed between the mold and the substrate. Particularly,in the case when the positional deviation in the in-plane direction iscaused to occur at a level exceeding a predetermined value, when thepositional deviation is corrected while retaining the distance betweenthe mold and the substrate, there is a concern about a possibility thatthe pattern area of the mold is physically damaged. For this reason, insuch a case, control of the distance between the mold and the substrateis effected so as to increase the distance. In a preferred embodiment,after the mold is moved away from the substrate to such a position thatindirect contact between the mold and the substrate via the resin isreleased, alignment of both of the mold and the substrate is effected.

As described above, positions of the mold and the work can be deviatedfrom each other as a result of application of a force in a directionparallel to the processing surface (the pattern area formed firstsurface) of the mold to the mold and the work during transfer of thepattern of the mold. Accordingly, the alignment in the in-planedirection parallel to the processing surface may preferably be effectedunder pressure application.

Incidentally, in this embodiment, as the substrate, it is possible touse a semiconductor substrate such as a Si substrate or a GaAssubstrate, a resin-coated semiconductor substrate, a resinous substrate,a glass substrate, etc. Further, it is also possible to use amulti-layer substrate prepared by growing or laminating a film on thesubstrate mentioned above. It is further possible to use alight-transmission substrate, such as a quartz substrate. Thesesubstrates are similarly used in the embodiments described hereinafter.

The alignment mark to be provided with respect to the substrate may beprovided directly with respect to the substrate itself or a filmlaminated on the substrate, or indirectly on a support member, or a basefor supporting the substrate. In the present invention, the substrateprovided with the alignment mark includes both the case where thealignment mark is provided with respect to the substrate itself and thecase where the alignment mark is provided with respect to the filmlaminated on the substrate.

An example (flow chart) of the pattern forming method of this embodimentis shown in FIG. 17B.

Referring to FIG. 17B, first, a mold provided with an alignment mark ata position away from a pattern area is prepared (P1).

The pattern area and a coating material (e.g., photocurable resin)formed on a substrate are caused to contact each other (P2). Thisoperation may preferably be performed after effecting alignment of themold with the substrate. Incidentally, onto the pattern area of themold, a fluorine-containing silane coupling agent, or the like, isapplied in advance as a release agent, in some cases, in order to permiteasy separation between the mold and the substrate after the curing ofthe resin. Accordingly, in the present invention, the contact of thepattern area (or the mold) with the coating material means both the casewhere they directly contact each other and the case where theyindirectly contact each other via another layer, such as the layer ofrelease agent. This is also true for other embodiments.

Next, in the contact state of the pattern area of the mold with thecoating material, alignment of the mold with the substrate is effected(P3). During the alignment, the coating material is also present in thearea (5300 shown in FIG. 17A) where the alignment mark in the in-planedirection of the mold and the alignment mark of the substrate areopposite to each other. It is also possible to remove the coatingmaterial from the area, but the alignment may preferably be effectedeven in the presence of the coating material in the area from theviewpoints of alleviation of severe control of the amount of coating ofthe coating material on the substrate and utilization of spin coating.

The alignment is effected in the following manner.

More specifically, alignment of the mold with the substrate is effectedin an in-plane direction of the pattern area-formed surface so that thepattern area of the mold is located at a desired position on thesubstrate. The mold and the substrate are relatively moved in thein-plane direction to effect the alignment.

During the alignment, as described above in this embodiment, positionaladjustment of the mold and the substrate is performed by using the markprovided with respect to the substrate and the alignment mark 2070provided with respect to the mold. Incidentally, the mold and thesubstrate are caused to come close to each other so that the gap(distance) between the mold and the substrate is a desired value, asdesired. During the gap (positional) adjustment, the positional controlin the in-plane direction may be effected or the position in thein-plane direction may be effected after the gap between the mold andthe substrate is once adjusted to provide a desired gap value. It isalso possible to place the positions of the mold and the substrate inthe in-plane direction and the gap therebetween in desired states byalternatively repeating the gap adjustment and the in-plane directionpositional adjustment.

Incidentally, measurement of the gap between the mold and the substratemay be performed by utilizing, e.g., a capacitance sensor or white lightspectroscopic ellipsometry.

Then, the coating material is cured (P4). In order to cure the coatingmaterial, heat or light, such as ultraviolet rays, is utilized. It isalso possible to cure the coating material by using heat and light incombination.

Thereafter, the mold is removed from the substrate (P5). As a result,the pattern of the mold is transferred onto the cured coating material.Then, the substrate or the film on the substrate is etched by using theuneven pattern provided on the cured coating material as a mask. Theetching may preferably be effected after a recessed portion of the curedcoating material layer is removed to expose a portion of the substrateimmediately under the coating material layer.

Fourth Embodiment Pattern Forming Method 2

In a pattern forming method of this embodiment, a mold described in theSecond Embodiment is used.

More specifically, as shown in FIG. 18A, alignment of a mold 104 with asubstrate 5000 is effected by using a second mark 2070 provided at aposition away from a first surface 1050 at which a pattern area 1000 isformed and an alignment mark (third mark) provided with respect to thesubstrate 5000. In FIG. 18A, 1060 represents a back surface (secondsurface) of the mold 104 opposite from the first surface 1050.

The substrate 5000 and the coating material 3000 on the substrate 5000may inclusively be referred to as the member to be processed (processingmember), but, in this embodiment, the case where a pattern is directlyformed on the substrate itself is also embraced.

In this embodiment, the alignment is effected by optically reading thesecond mark 2070 and the third mark 5030 from the mold side by means ofan image pickup device and relatively moving the mold and the substratein the in-plane direction so that the second and third marks have apredetermined positional relationship. In this case, either one or bothof the mold and the substrate may be moved.

In FIG. 18A, a first mark 2077 is formed at the same surface as thefirst surface.

In this embodiment, information about the positional relationshipbetween the first mark 2077 and the second mark 2070 is obtained inadvance and, by using the information, the alignment of the mold withthe substrate may preferably be effected. This is because it isordinarily difficult to ensure the positional relationship between thepattern area 1000 and the second mark provided at the surface oppositefrom the pattern area-formed surface on the order of nanometers asdesigned.

More specifically, even when the second mark is designed so as to beprovided at a position away from the pattern area by S in the in-planedirection, in many cases, the second mark is actually provided at aposition away from the pattern area by S+α including an error α. On theother hand, the positional relationship between the pattern area and thefirst mark formed on the surface as the pattern area can be ensured, sothat the first mark is actually formed at a position substantiallyidentical to the designed position, on the order of nanometers. Forexample, in a step of forming the pattern area through an electron beamimage forming method, when the mark portion is together formed throughthe same method, the mark can be formed actually at a position with lesserror from the designed position.

According to this embodiment, the alignment mark is provided at the twosurfaces of the mold, so that it is possible to ensure the positionalrelationship between the pattern area 1000 and the second mark 2070.

The first mark 2077 is substantially provided at the designed position,although an error of several nanometers can occur. Accordingly, anactual position of the second mark designed to be located at a positionaway from the pattern area by S can be determined by obtaininginformation about the positional relationship between the first mark2077 and the second mark 2070 (e.g., their positions in the in-planedirection). Accordingly, alignment can be effected with high accuracy byutilizing the second mark 2070 and the third mark 5300. In other words,when the first mark is invisible, it is possible to effect the alignmentof the mark with the substrate by using the second mark of which thepositional relationship with the first mark is determined.

With respect to the positional relationship between the first mark andthe second mark, it may be not only directly determined, but also,indirectly determined on the basis of another mark X and informationabout the positional relationship can also be utilized. In this case,the position of the mark X may preferably be located at the same surfaceas either one of the first mark and the second mark.

The pattern forming method of this embodiment is also characterized inthat the alignment of the mark with the processing member (or thesubstrate) in the in-plane direction of the pattern area surface iseffected by using first positional information about a relativepositional relationship between the first mark provided at the patternarea surface and the second mark provided at a position away from thepattern area-formed surface and second positional information about arelative positional relationship between the second mark provided at theposition away from the pattern area-formed surface and the surface markprovided with respect to the processing member.

According to the above constitution, it is possible to accurately detectthe positions of the mold and the work to effect the alignment of themold with the work. This is attributable to accurate position detectionperformed without being adversely affected, even in the case when thephotocurable resin contacts the mark by effecting the alignment of themold with the work under pressure application, different from theconventional pattern forming method, as a result of study by the presentinventors.

More specifically, according to the above-described constitution, thealignment can be realized by comparing the relative position of the markprovided at the processing surface and the mark provided at the positionaway from the processing surface with the relative position of the markprovided at the position away from the processing surface and the markprovided with respect to the processing member. According to such aconstitution, even in a state in which the mark provided at theprocessing surface of the mold contacts the photocurable resin to lowera signal contrast, it is possible to align the position of the mold withthe position of the substrate.

More specifically, a positional relationship between the mark providedat the surface of the mold and the mark provided at a surface away fromthe surface via a member when they are projected on a plane parallel tothe processing surface of the mold is preliminarily measured by theimage pickup device, or the like. This is a necessary measurement since,as described above, it is easy to form a pattern including a mark in thesame plane within a desired error, but it is difficult to ensure apositional relationship between the mark provided at the surface of themold and the mark provided at the position away from the surface of themold. The measurement can be omitted in the case where the positionalrelationship therebetween is determined in advance.

Next, a positional relationship between the mark provided at theposition away from the mold surface and the mark provided with respectto the substrate is measured by the image pickup device, or the like.

By comparing both of the measured values of the above-described twopositional relationships, it is possible to accurately detect thepositions of the mold and the substrate.

According to the above-described measurement method, it is possible totransfer the pattern of the mold onto the substrate with high accuracy,even in the contact state of the mark at the processing surface with thephotocurable resin.

The above-described pattern forming method can be utilized insemiconductor production technology, production technologies of anoptical device such as a photonic crystal and a biochip, such as a μTAS, etc.

According to an aspect of the present invention, the mold ischaracterized in that it has the first mark provided at the patternformed surface and the second mark provided at the position (the imageportion or the back (opposite) surface of the mold) away from thehorizontal position of the pattern-formed surface. So long as therelative positional relationship between these two marks is determined,positions of these marks are not limited. In the case when thepattern-formed surface (front surface) of the mold is viewed from theback surface side of the mold, i.e., in the case when the pattern formedsurface is viewed in a direction normal thereto, both patterns mayoverlap with each other, but are not necessarily required to overlapwith each other. The first mark is not particularly limited so long asit is located at the processing surface of the mold. However, from theviewpoint of preparation of the mold, it is preferable that the firstmark is provided at the same horizontal position as the pattern formedsurface (processing surface) of the mold.

The third mark provided with respect to the processing member may beprovided with respect to the substrate itself constituting theprocessing member or with respect to the support member for supportingthe substrate.

During the positional adjustment, alignment of the mold surface with thesubstrate to be processed by measuring a positional deviation betweenthe mold and the substrate utilizing the second mark and the third mark,and by controlling well the positional deviation in consideration of therelative position of the first mark and the second mark.

The alignment may preferably be performed through a step of storingfirst error information as a horizontal and rotational error of thefirst mark on the basis of the second mark, a step of storing seconderror information as a horizontal and rotational error of the third markon the basis of the second mark, and a step of horizontally androtationally moving the substrate relative to the mark, so that thefirst error information and the second error information are inagreement with each other.

Further, the alignment may preferably be effected by storing first errorinformation about at least one of a horizontal error or a rotationalerror between the second mark and the first mark, storing second errorinformation about at least one of a horizontal error or a rotationalerror between the second mark and the third mark, and effecting at leastone of an operation for horizontally moving the processing memberrelative to the mold and an operation for rotationally moving theprocessing member relative to the mold by using the first error and thesecond error.

In the present invention, the alignment in the in-plane directionbetween the processing member (or the substrate) and the mold (or thepattern area of the mold) at least embraces the following three cases.

More specifically, on the precondition that the pattern area of the moldand the processing member are parallel to each other, there are firstand second cases. The first case is the case when both members arerelatively moved horizontally or rotationally to effect the alignment.The second case is the case in which both members are relatively movedhorizontally and rotationally to effect the alignment. Here, the term“moved rotationally” means, e.g., that the processing surface of themold is rotated, relative to the substrate, around an axis perpendicularto the surface plane. Further, on the precondition that the processingmember and the mold are not parallel to each other, there is a thirdcase wherein both members are relatively rotated so that their surfacescome close to a parallel state. Here, the term “relatively rotated”includes the case where an angle of a normal to the pattern formedsurface of the mold with respect to the axis perpendicular to thesurface plane is changed.

An example (flow chart) of the pattern forming method according to thisembodiment is shown in FIG. 18B.

First, the mold having the above-described first and second marks isprepared (P11).

Next, the pattern area and the coating material on the substrate arecaused to contact each other (P22). In this example, the substratehaving the coating material corresponds to the processing member.

Then, the alignment of the mold with the substrate is effected byoptically reading the second mark and the third mark on the substrateside. In this case, the alignment is effected by using information aboutthe positional relationship between the first mark and the third mark ofthe mold (P33). This information is obtained by reading both of thefirst and second marks by the image pickup device. As a result, even inthe case when the second mark position is not ensured, it is possible toeffect high-accuracy alignment using the second mark and the third markon the substrate side. The alignment to be actually effected is suchthat the pattern area is adjusted to a desired position on thesubstrate, so that the alignment is required in some cases so as toobtain the positional relationship such that the second mark and thethird mark, which are optically observed, do not overlap with eachother.

After the alignment of the mold with the substrate is completed, thecoating material is cured (P44). Thereafter, the mold is removed fromthe substrate (P55). As a result, pattern formation is completed.

The above-described steps P11, P22, P44 and P55 are the same as those inthe steps P1, P2, P4 and P5 described in the Third Embodiment withreference to FIG. 17A, so that specific explanations thereof areomitted.

Incidentally, the step P44 is omitted in the case when the processingmember is the substrate itself, and the pattern is formed by applying apressure between the mold and the substrate. In this case, it is alsopossible to apply heat to the substrate to soften the substrate.Further, in the case of using the substrate itself as the processingmember, the mold is removed from the substrate itself in step P55.

The step P33 will be described more specifically.

During the alignment in the step P33, the coating material may bedisposed on the substrate so that it is present or not present in thearea (5300 shown in FIG. 17A) where the second mark provided on the moldside and the third mark provided on the substrate side are opposite toeach other.

More specifically, alignment of the mold with the substrate is effectedin an in-plane direction of the pattern area-formed surface so that thepattern area of the mold is located at a desired position on thesubstrate. The mold and the substrate are relatively moved in thein-plane direction to effect the alignment.

During the alignment, as described above in this embodiment, positionaladjustment of the mold and the substrate is performed by using the thirdmark provided with respect to the substrate and the second mark 2070provided with respect to the mold. During the positional adjustment, theposition of the second mark is deviated from the designed position insome cases, so that the alignment is effected in consideration of thepositional relationship between the first mark and the second mark.Incidentally, the mold and the substrate are caused to come close toeach other so that the gap (distance) between the mold and the substrateis a desired value, as desired. During the gap (positional) adjustment,the positional control in the in-plane direction may be effected or theposition in the in-plane direction may be effected after the gap betweenthe mold and the substrate is once adjusted to provide a desired gapvalue. It is also possible to place the positions of the mold and thesubstrate in the in-plane direction and the gap therebetween in desiredstates by alternatively repeating the gap adjustment and the in-planedirection positional adjustment.

Incidentally, it is also possible to effect a two stage alignment byusing the first mark provided at the pattern area-formed surface of themold and the second mark provided away from the pattern area-formedsurface in the thickness direction of the mold. For example, in such astate that the mold and the substrate (or the processing member) aresufficiently apart from each other, a first-stage alignment using thefirst mark is effected. Thereafter, the mold and the substrate arecaused to come gradually near to each other and, e.g., when the firstmark is less visible, a second-stage alignment using the second mark iseffected.

Fifth Embodiment Pattern Forming Apparatus

A pattern forming apparatus according to this embodiment is providedwith a mold holding portion and a substrate support portion (or aprocessing member support portion) in order to effect the patternformation described in Embodiments 3 and 4. The mold holding portion andthe substrate support portion are configured to be relatively moved inthe in-plane direction.

Further, the pattern forming apparatus may preferably have a positionaldeviation detection mechanism for detecting the positional deviationbetween the pattern area of the mold and the coating material in acontact state therebetween and a gap (distance) control mechanism forcontrolling the gap between the substrate and the mold on the basis ofdetection information from the detection mechanism.

Next, the pattern forming apparatus provided with the mold according tothe present invention will be described.

As shown in FIG. 4, the pattern forming apparatus includes a lightsource 201, an optical measuring system 202, an imprinting controlsystem 203, a work pressing mechanism 204, an in-plane moving mechanism205, a mold pressing mechanism 206, a light source 207, an analysissystem 208, an image pickup device 209, a microscope 210, a mold sidealignment structure 211, a work-side alignment structure 212, a mold213, a photocurable resin 214, and a work 215.

In FIG. 4, such an example that the alignment mark (alignment structure)211 is provided with respect to the mold 213 at a position away from apattern area is shown. However, to the mold 213, those described inEmbodiment 1 or Embodiment 2 are applicable.

The optical measuring system 202 is provided with a constitution capableof detecting XY-direction information and Z-direction information.Herein, the XY-direction is the above-described in plane direction andthe Z-direction is a direction perpendicular to the processing surface.The in-plane direction is, as described above, the direction parallel tothe surface at which the pattern area to be transferred is formed.

The information, about the in-plane direction and the Z-direction of themold 213 and the work 215, measured by the optical measuring system 202,is fed back to the imprint control system 203.

The work pressing mechanism 204 supports the work 215 on the in-planemoving mechanism 205, thus being considered as a work support means.

In this embodiment, it is also possible to use a load cell, not shown,or the like, for measuring a pressure applied to the work 213 and themold 215.

Next, a processing method using the processing apparatus having the moldwill be described with reference to FIGS. 5A and 5B, each showing a flowchart thereof in this embodiment.

In FIG. 5A, Step S1 is a step, at a so-called coarse adjustment stage,for effecting Z-direction movement (1) by which the mold is moved to aset position so as to come close to the work with a set distance, whilemaking reference to an encoder of a motor and a Z-direction positionaldetector. The set distance, e.g., corresponds to a position at which themold starts to contact the photocurable resin. After the mold is movedto the set position, the operation goes to Step S2, in which in-planeposition detection (1) is effected.

Next, the procedure goes to Step S3-1. When the detected value iscompared with a set value in the in-plane direction and satisfiesCondition (1), the operation goes to Step S4 for performing Z-directionmovement (2) as a step at a fine movement stage. In this step, amovement distance may be a predetermined value or changed depending on adistance between the mold and the work. After completing Step S4 at thefine movement stage, the operation is ended when an end condition inStep S5 is fulfilled.

Here, Condition (1) can be set to be, e.g., whether the detected valueis less than several fractions of a minimum line width (e.g., severaltens of nm) of a pattern. In the case where Condition (1) is notfulfilled, Condition (2) (Step S3-2) is judged. In the case whereCondition (2) is fulfilled, the operation goes to Step S3-3 in whichmovement in the in-plane direction is performed.

Condition (2) can be set to be, e.g., whether the detected value is in arange of more than several fractions of the minimum line width and lessthan the minimum line width. In the case where Condition (2) is notfulfilled, the operation goes to Step S3-4 in which Z-direction movement(3) is effected to move the mold away from the position after completingthe Z-direction movement (1). The moved position may be a position atwhich the mold contacts the photocurable resin, the position before orduring Z-direction movement (1), or the original position. Thereafter, adistance parameter for Z-direction movement (2) may be changed.

The above-described operations are repetitively performed until the endcondition in Step S5 is satisfied. A value of the end condition may be adistance or a pressure.

Further, even in a state in which an operation for causing the mold tocome close to the work, positional detection of the mold and the work iseffected and the detection results are fed back to the in-plane movingmechanism.

FIG. 5B is a flow chart different from that of FIG. 5A.

Similarly, as in Step S1 of FIG. 5A, after the coarse adjustment formoving the mold to the set position so as to come close to the work withthe set distance while making reference to the encoder of the motor andthe Z-direction positional detector, Z-direction movement (4) in Step S2and in-plane position detection in Step S2-1 are performed by parallelprocessing. Here, Z-direction movement (4) may be controlled by adistance or a speed. Further, these control methods may be changeddepending on the direction between the mold and the work. Z-directionmovement (4) is continuously performed until an end condition (Step S4)is satisfied or an interrupt (Step S3-1) occurs. The interrupt occurs inthe case of satisfying Condition <<3>> of case division in Step S2-2.With respect to the case direction, for example, Condition <<1>> is lessthan several fractions of a minimum line width, Condition <<2>> is notless than Condition <<1>> and less than the minimum line width, andCondition <<3>> is not less than Condition <<2>>.

In the case where Condition <<1>> is satisfied, the operation isreturned to In-plane position detection in Step S2-1. In the case whenCondition <<2>> is satisfied, the operation goes to in-plane positionmovement in Step S2-3 in which in-plane position movement is effected,but the interrupt does not occur. In the case when Condition <<3>> issatisfied, the operation goes to Step S3-1 in which the interruptoccurs.

In the case in which the interrupt occurs, Z-direction movement (3)(Step S3-2) is effected similarly as in Step S3-4 in FIG. 5A.

The above-described operations are performed until the end condition inStep S4 is satisfied.

As described above, after the mold is once caused to contact thephotocurable resin, in the case when the position of the mold is largelymoved in the in-plane direction while retaining the same Z-directionposition when Condition (2) shown in FIG. 5A is not satisfied, there isa possibility that the mold and the work are damaged. For example, inthe case when the mold and the work are close to each other (e.g.,within several tens of nm), large forces (such as frictional forces) canbe generated at the mold surface and the work surface in directionsopposite from each other by the movement of the mold in the in-planedirection depending on a viscosity of the photocurable resin. This meansthat the patterns of the mold and the wafer are damaged. In theimprinting, the patterns of the mold and the work are resistive to aforce in a vertical direction as described later, but are liable to bedamaged by the force in the in-plane direction as described above.

According to the constitution of this embodiment, when a largepositional deviation is detected after the contact of the mold with thework, the mold is once moved away from the work in Z-direction and thenis moved in the in-plane direction to obviate the damage describedabove. Further, as described above, the alignment structure is providedat the position away from the pattern area, so that the alignmentstructure is not contaminated with the photocurable resin by attachmentof the photocurable resin in the state of contact with the photocurableresin, thus permitting accurate positional detection.

The above-described damage of the patterns of the mold and the work inthe in-plane direction and the contamination of the alignment structurewith the photocurable resin by the contact of the mold with thephotocurable resin will be described below more specifically.

FIG. 6 and FIGS. 7A and 7B are schematic views for illustrating theseparticular phenomena in the imprinting.

In FIG. 6, a mold 903 is provided with a broader groove structure (A)901 and a narrower groove structure (B) 902. On a work 905, aphotocurable resin 904 is disposed.

As shown in FIG. 6, in the case when a pattern surface constituted bythe broader groove structure (A) 901 and the narrower groove structure(B) 902 in combination is formed on the mold 903, the photocurable resin904 is first filled in the narrower groove structure (B) 902 when themold 903 and the work 905 are caused to come close to each other. As aresult, stresses applied to the broader groove structure (A) 901 and thenarrower groove structure (B) are different from each other, so that aninclination is caused to occur between the mold 903 and the work 905 toresult in slippage therebetween. As a result, positional deviation iscaused to occur in some cases. An amount of the positional deviation isgradually accumulated with a decrease in distance between the mold andthe work. In this case, when the mold and/or the work is moved largelyin the in-plane direction, the mold and the work can be damaged in somecases. This is attributable to the following phenomenon described belowwith reference to FIGS. 7A and 7B.

In these figures, 1000 represents a mold, 1002 represents a forceapplied in the vertical direction, 1003 is a force applied in thein-plane direction, 1004 represents a torque, 1005 represents an axisduring breakage, and 1006 represents a starting point during breakage.

In these figures, the mold is explained, for example, but the work isalso similarly applicable.

As shown in FIG. 7A, in the case when the vertically pressing force isapplied to the mold, the force is substantially uniformly applied to theentire surface of the mold.

On the other hand, as shown in FIG. 7B, in the case when the force inthe in-plane direction is applied to the mold, an interface between thepattern and the substrate does not receive a uniform force. For example,with respect to a pulling force concentrated at edge portions, the moldis liable to be broken with an edge as an axis 1005 and another edge asa starting point 1006. This breakage is noticeable when an aspect ratiois larger, since a rotation torque is larger with the larger aspectratio.

In such a case, according to the processing method of this embodiment,when a large positional deviation is detected after the contact betweenthe mold and the work, the mold is once moved away from the work in theZ-direction, and then is moved in the in-plane direction as describedabove, so that it is possible to obviate the above-described damage.

Further, with respect to the alignment of the mold with the work, themold-side alignment structure and the work-side alignment structure areoptically observed by the optical measuring system 202 to effectalignment of these alignment structures.

FIG. 8 is a schematic view for illustrating a troublesome state createdbetween the alignment structures of the mold 1103 and the work 1105.

In FIG. 8, 1101 represents detection light, 1102 representsscattering/refracting light, 1103 represents the mold having analignment structure, 1104 represents a photocurable resin, and 1105represents the work having an alignment structure.

As shown in FIG. 8, in the case when the photocurable resin 1104 isinterposed between the mold 1103 and the work 1105, when a distancebetween the mold and the wafer is decreased, a surface of thephotocurable resin 1104 is not flat. For this reason, the detectionlight 1101 is scattered or refracted (1102) at the surface of thephotocurable resin 1104, so that the alignment structure is unclear.Further, in the case when a difference in refractive index between thephotocurable resin and the mold using a light-transmissive alignmentstructure is small, it is difficult to detect the alignment structurewhen the mold and the photocurable resin completely contact each other.Further, in the case when the mold is caused to contact the work todetect the positional deviation, before the photocurable resin is cured,and then is once moved away from the work in Z-direction, accuratealignment is prevented when the photocurable resin attaches to thealignment structure of the mold.

In these cases, according to the present invention, if the alignmentstructure of the mold is provided in such an area that it does notcontact the photocurable resin as described above, it is possible toimprove an accuracy of the alignment. Incidentally, the above-describedmold may suitably be used for the alignment constitution and theposition detection method in this embodiment, but other molds capable ofproviding a necessary detection resolution are also applicable.

Sixth Embodiment Pattern Transfer Apparatus

A pattern transfer apparatus according to this embodiment has analignment mechanism for effecting alignment of a mold with a member tobe processed, the alignment mechanism is characterized by beingconfigured to effect alignment of the mold with the processing member(the substrate) in an in-plane direction of a pattern area of the moldby using first positional information about a relative positionalrelationship between a first mark provided at a surface of the mold atthe same level as a pattern area formed surface of the mold and a secondmark located away from the pattern area formed surface and using secondpositional information about a relative positional relationship betweenthe second mark and a third mark provided to the processing member.

More specifically, as the pattern transfer apparatus of this embodiment,it is possible to utilize the same apparatus as that described withreference to FIG. 4.

As a characteristic feature of this embodiment, actual alignment iseffected by using the second mark and the substrate-side third mark.During this alignment, alignment is effected in consideration of thefirst positional information about the relative positional relationshipbetween the first mark and the second mark.

The second mark is, as described above, provided at a position deviatedfrom the actually designed position with an error in some cases.Accordingly, in consideration of this error, alignment of the secondmark with the third mark can be effected. In other words, alignment canbe substantially effected by the first mark and the third mark.

In this embodiment, the alignment mechanism may preferably include afirst storing portion for storing the first positional information and asecond storing portion for storing second positional information.

Embodiment 1

A mold having an uneven pattern according to the present invention isused so that the uneven pattern is pressure-transferred onto aprocessing member (member to be processed) formed of resin byimprinting.

FIGS. 9A to 9E are schematic views for illustrating an imprint process.

In these figures, 401 represents a work (substrate in the embodimentsdescribed above), 402 represents a mark, 403 represents a photocurableresin, 404 represents a third alignment structure (third alignmentmark), 405 represents a second alignment structure (second alignmentmark), 406 represents an uneven pattern of the mark 402, and 407represents a light incident direction.

In this embodiment, as a material for the mold 402, it is possible touse a light-transmissive substance such as quartz, pyrex (registeredtrademark), or sapphire. The surface of the mold 402 is principallysubjected to microprocessing by EB lithography, FIB, X-ray lithography,etc., or is subjected to replica formation from electroformed Ni, etc.As the work 401, it is possible to principally use a semiconductor wafersuch as a Si wafer or a GaAs wafer, a resin-coated wafer, a resinousplate, a glass plate, etc.

Next, the imprint process in this embodiment will be described.

First, the photocurable resin 403 is applied onto the work 401 providedwith the third alignment structure 404 (FIG. 9A).

Next, the mold 402 provided with the second alignment structure 405 andthe work 401 are disposed opposite to each other to effect alignment ofthe mold 402 with the work 401 (FIG. 9B). More specifically, thealignment can be effected by, e.g., a box, a cross, a bar, a moirefringe, or the like. By observing these shapes or fringes and subjectingthem to image processing, it is possible to effect the alignment.Details of the apparatus will be described later. In FIG. 9B, the secondalignment structure 405 as the second mark is provided at the positionaway from the mold surface. The second mark, however, can also beprovided at such a position that it does not contact the resin asdescribed with reference to FIGS. 2A-2D. Further, in FIG. 9B, the resin403 is not present at a portion where the second mark and the work areopposite to each other, but may be present at the portion.

Then, a distance between the mold 402 and the work 401 is decreased, andthe mold 402 and the work 401 are kept at a position where a setpressure or a set distance is ensured (FIG. 9C).

Thereafter, the resultant structure is irradiated with light 407 to curethe photocurable resin 403 (FIG. 9D).

Finally, the mold 402 is moved away from the work 401 to transfer thepattern of the mold 402 onto or into the photocurable resin 403 on thework (substrate) 401 (FIG. 9E).

In this embodiment shown in FIGS. 9A to 9E, the alignment mark (secondalignment structure 405) of the mold is formed at the position away fromthe pattern area surface. However, so long as the mold has such analignment mark that it does not contact the resin 403, it is alsopossible to provide the mold 402 with the alignment mark on the backsurface of the mold 402, for example.

Details of the alignment structure in this embodiment will be describedwith reference to FIG. 10 showing a constitutional example of analignment structure having a periodic structure in this embodiment.

In FIG. 10, a mold 505 has a processing surface 501, an uneven pattern502, a light-blocking film 503, and a height A 504 of the uneven pattern502.

With respect to the alignment of the mold with a work, in the case whenan accuracy of the alignment is larger than an optical resolution, it ispossible to use a box, a cross, a bar, etc. In the case of requiring anaccuracy less than the optical resolution, it is also possible to employa high-level image processing or a periodic structure or a combinationof these. Incidentally, in the case of using the periodic structure, asshown in FIG. 10, the periodic structure can also be provided as theuneven pattern 502 including grooves or as the light-blocking film 503of Cr, or the like.

FIGS. 11A and 11B show examples of alignment structures using a periodicstructure.

In FIG. 11A, 601 represents a work side alignment structure (A), 602represents a mold-side alignment structure, 503 represents a patternhaving a period p1, and 604 represents a pattern having a period p2. Inthis example, the patterns 603 and 604 are arranged in parallel witheach other.

The mold having the alignment structure (A) 601 and the work having thealignment structure (B) 602 are disposed so that these structures areopposite to each other.

More specifically, the work-side pattern 603 and the mark-side pattern604 overlap with each other. Further, the work-side pattern 604 and themark-side pattern 603 overlap with each other. As a result, in each ofoverlapping two areas, a moire fringe is observed. In the two areas,periods of two moire fringes are identical to each other and when theyare in-phase, positions of the mold and the work are matched. In otherwords, a positional relationship between the mold and the work isdetermined.

FIG. 11B shows another constitutional example of the alignment structurein this embodiment.

In FIG. 11B, 702 represents a uniaxial alignment structure and 702represents an X.Y.θ alignment structure.

In order to detect alignment factors (X, Y, θ) in the in-plane directionby a single alignment structure, as shown by the alignment structure 701in FIG. 11B, the alignment structure 601 shown in FIG. 11A is rotatedninety degrees so as to provide the alignment structure shown in FIG.11B. The number of the alignment structures may be one, but twoalignment structures are required for effecting magnificationcorrection. Further, in order to effect distortion correction, at leastone alignment structure is additionally required.

FIGS. 16A and 16B show arrangement examples of the alignment structure.

In these figures, 801 represents a mold (A), 802 represents a mold (B),803 represents a pattern (A), 804 represents a pattern (B), and 805represents an arrangement position of the alignment structure.

As shown in the mold (A) 801 of FIG. 16A, the alignment structure isarranged at four corners of the pattern (A) 803, so that redundancy isincreased to permit improvement in positional accuracy. Further, asshown in the mold (B) 802 of FIG. 16B, an alignment structure may alsobe arranged in an area subjected to dicing of the wafer.

According to the embodiment described above, it is possible to realizethe alignment of the mold with the work in the in-plane direction withhigh accuracy.

Embodiment 2

In this embodiment, a constitutional example of the mold according tothe present invention is described with reference to FIGS. 19A to 19C.

In these figures, the constitution includes a mold 19101, a pattern area(pattern area) 19102, a first position measuring mark 19103, a firstalignment mark 19104 (the second mark in the Second Embodiment), asecond position measuring mark 19105 (the first mark in the SecondEmbodiment), and a processing pattern alignment mark 19106.

FIG. 19A is a schematic view of the constitution when the mold 19101 isviewed from a back surface side opposite from the pattern area providedat a front surface of the mold 19101.

Here, the back surface is a surface where there is no processing patternin the pattern area 19102 and the front surface is a surface where theprocessing pattern is formed in the pattern area 19102.

At each of four corner portions of the mold 1901 on the back surfaceside, the first position measuring mark 19103, the first alignment mark19104 (second mark), and the processing pattern alignment mark 19106 aredisposed.

At each of four corner portions of the mold 19101 on the front surfaceside, the second position measuring mark 19105 (first mark) is disposed.

Incidentally, the position measuring marks 19103 and 19105 are marks formeasuring a relative positional relationship between the mark backsurface and the surface pattern of the mold. Further, the firstalignment mark 19104 (second mark) is a mark for positionally aligningthe mold and the substrate relative to each other. The processingpattern alignment mark 19106 is a reference mark during preparation ofthe processing pattern.

FIG. 19B is an A-A′ sectional view of FIG. 19A, wherein the secondposition measuring mark 19105 (first mark) is disposed at the frontsurface of the mold, and the first position measuring mark 19103 isdisposed at the back surface of the mold.

FIG. 19C is a B-B′ sectional view of FIG. 19A, wherein the firstalignment mark 19104 (second mark) and the processing pattern alignmentmark 19106 are disposed at the back surface of the mold.

These marks are constituted so that they are suitable for measuringrespective positions and may have ordinary shapes such as a bar, across, a circle, a rectangle, and combinations of these.

Incidentally, the first alignment mark 19104 (second mark) and the firstposition measuring mark 19103 of the mold may only be required to bedisposed at positions away from the front surface of the mold via amember. Further, the processing pattern alignment mark 19106 may also beprepared by utilizing the first alignment mark 19104 (second mark).

FIGS. 20A to 20E each shows a constitution example of the marks in thisembodiment.

FIG. 20A shows such a constitution that the above-described firstposition measuring mark, the first alignment mark, and the processingpattern alignment mark are provided at the back surface of the mold byutilizing the presence or absence of or difference in density of thetransparent member forming the mold. As shown in FIG. 1, theconstitution includes a first transparent member 19201, a mark area19202, a pattern area 19203, a front surface 19204, a back surface19205, a front surface-side mark 19206, and a back surface side mark19207.

The mold is formed of the first transparent member 19201 and has themark area 19202 and the pattern area (processing area) 19203. The firsttransparent member can be formed of quartz, pyrex (registeredtrademark), sapphire, etc.

At the front surface 19204 of the mold, a processing pattern is formed.

At the back surface 19205 of the mold, the first position measuringmark, the first alignment mark, and the processing pattern alignmentmark are formed in the mark area 19202. Further, in the mark area 19202,the second position measuring mark is formed at the front surface of themold as the front surface-side mark.

Incidentally, in FIG. 20A, the front surface side mark and the backsurface-side mark are depicted so that they are coaxially aligned, butmay also be formed in such a manner that they are relatively shifted ina horizontal direction. The processing pattern alignment mark may alsobe formed at the front surface of the mold depending on the moldproduction process.

FIG. 20B shows such a constitution that the marks (mark group) providedat the back surface of the mold in the constitution shown in FIG. 20Aare provided at an inner portion 19208 of the mold. The inner portion19208 is formed by utilizing the presence or absence or a difference indensity of the transparent member constituting the mold.

FIG. 20C shows such a constitution that the marks (mark group) providedat the back surface of the mold are constituted as a mark 19209 providedwith respect to a second transparent member. The second transparentmember is formed of quartz, pyrex (registered trademark), sapphire, ITO,titanium oxide, etc., and may be somewhat different in composition fromthe first transparent member.

FIG. 20D shows such a constitution that the mark group is constituted bya mark 19210 provided at the back surface of the mold at a portion freefrom the first transparent member by embedding the mark group formed ofthe second transparent member in the portion.

FIG. 20E shows such a constitution that the mark group is constituted bya mark 19211, formed of the second transparent member, provided at theback surface of the mold at a portion projected from the firsttransparent member.

In the case of the constitutions shown in FIG. 20D or FIG. 20E, thesecond transparent member may also be changed to a metallic member, orthe like.

Embodiment 3

In this embodiment, a process for producing the mold according to thepresent invention is described.

FIGS. 21A to 21G show steps of the mold production process in thisembodiment, wherein processing is effected by turning the mold upsidedown. In this process, first, one surface of the mold is processed andthen the other surface of the mold is processed.

More specifically, first of all, a substrate 19301, of a transparentmember onto which a resist 19304 is applied, is prepared (FIG. 21A). Thesubstrate 19301 has a front surface 19302 on which a processing patternis disposed and a back surface 19303.

Next, in order to create a mark group at the back surface of thesubstrate, light exposure and development are effected (FIG. 21B). Themark group includes the first position measuring mark, the firstalignment mark, and the processing pattern alignment mark.

Then, the substrate is etched to transfer a mark group 19305 at the backsurface of the substrate (FIG. 21C).

Next, the substrate is turned upside down (FIG. 21D).

Then, onto the front surface 19302, the resist 19304 is applied (FIG.21E).

Thereafter, alignment is effected while observing the processing patternalignment mark at the back surface of the substrate, followed by lightexposure and development of a processing pattern 19306 and a secondposition measuring mark 19307 (FIG. 21F). For this purpose, as a lightexposure apparatus, a double-sided aligner is used.

Next, the substrate is etched, and the resist is removed to complete amold having the processing pattern 19306 and the second positionmeasuring mark 19307 (FIG. 21G).

Incidentally, the front surface portion and the back surface portion maybe separately formed on two substrates and then may be applied to eachother to prepare a mold having the first mark 19305, the processingpattern 19306, and the second portion measuring pattern 19307.

Generally, in the mold prepared above, positions of the patterns on thesame plane are ensured with a desired accuracy.

On the other hand, between different planes, such as the front surfaceand the back surface, a positional accuracy between the respectiveplanes is low.

Accordingly, it is considered that the first alignment mark, the firstposition measuring mark, and the processing pattern alignment mark arearranged at desired positions. Further, the second position measuringmark and the processing pattern are disposed at desired positions.

On the other hand, a positional relationship between the first alignmentmark and the processing pattern is uncertain, since these are not on thesame plane as described above.

However, the mold in this embodiment has the first position measuringmark and the second position measuring mark. Accordingly, by using thefirst position measuring mark and the second position measuring mark, incombination, and measuring a positional relationship therebetween bymeans of a relative position measuring means configured to be used in apressure processing apparatus in an Embodiment of the present inventionappearing hereinafter, it is possible to clarify the positionalrelationship.

Embodiment 4

In this embodiment, another mold production process according to thepresent invention will be described.

FIG. 22 shows a constitutional example of a pattern forming apparatus inthis embodiment.

As shown in FIG. 22, the pattern forming apparatus includes an exposurelight source 19401, an optical system 19402, an optical system drivemechanism 19403, an analysis mechanism 19404, a mold holding portion19405, a body tube 19406, a work holding portion 19407, a work pressingmechanism 19408, an in-plane moving mechanism 19409, an imprint controlmechanism 19410, and an unshown measuring mechanism for measuring a gapbetween the mold and the work. In FIG. 22, 19412 represents the work(substrate) and 19413 represents a coating material for coating at leasta part of the substrate 19412. The mold 19411 is subjected to chuckingwith the mold holding portion 19405 so that the mold 19411 is disposedat a position opposite to the work. The work is constituted by thesubstrate 19412 onto which the coating material 19413 of a photocurableresin is applied by spin coating. The work is movable to a desiredposition by the in-plane moving mechanism 19409. Further, by the workpressing mechanism 19408, it is possible to effect adjustment of heightof the work and pressure application to the work.

The exposure light source 19401 reaches the mold through the body tube19406.

The imprint control mechanism 19401 controls positional movement of thework, pressure application to the work, the optical system drivemechanism 19403, and light exposure.

In this embodiment, a principal portion of an alignment mechanism foreffecting alignment of the mold with the work is constituted by theoptical system 19402, the optical system drive mechanism 19403, and theanalysis mechanism 19404.

The optical system 19402 is movable to an in-plane direction parallel tothe work and a direction perpendicular to the work by the optical systemdrive mechanism 19403.

Data obtained by the optical system is analyzed using the analyzingmechanism 19404. The analyzing mechanism 19404 is configured to measurea relative position between the mold and the work or a relative positionbetween the front surface and the back surface of the mold and to becapable of storing the measured values thereof.

Next, the optical system in this embodiment will be further described.

FIGS. 23A and 23B are schematic views for illustrating a constitution ofthe optical system using reference marks in the pressure processingapparatus of this embodiment, wherein FIG. 23A is a view showing aconstitution of the entire optical system and FIG. 23B is a view showingmarks observed through an image pickup device.

In this embodiment, the optical system is configured to use referencealignment marks. Such a constitution is, e.g., described in JapaneseLaid-Open Patent Application No. Hei 10-335241.

More specifically, first, a mold 19501 and a work 19502 are locatedopposite to each other with a certain gap therebetween. The work in thisembodiment is constituted by the above-described substrate coated withthe resin.

The mold in this embodiment has a first alignment mark 19503 (the secondmark in the embodiment described above) and a first position measuringmark 19505 at a back surface and has a second position measuring mark19506 (the first mark in the embodiment) at a front surface.

On the other hand, the work has a second alignment mark 19504 (the thirdmark in the embodiment).

Next, observation of the first alignment mark 19503 and the secondalignment mark 19504 will be described.

Light from a light source 19511 passes through an illumination system19510 and a reference mark substrate 19507 and is reflected by beamsplitters toward second imaging systems 19516 and 19518.

The above-described reference mark substrate is a substrate providedwith marks, at the front surface and the back surface, of which apositional relationship is clarified when the marks are projected ontoone of the front surface and the back surface. For example, thereference mark substrate is such a substrate that two marks are formedso that the two marks overlap with each other when the marks areprojected onto the front surface of the substrate.

Each of a first reference mark 19509 and a second reference mark 19508is configured to provide an optical conjugation relationship with thefollowing mark group.

More specifically, the first reference mark 19509 is opticallyconjugated to a mark group A (the first position measuring mark 19505and the first alignment mark 19503), and the second reference mark 19509is optically conjugated to a mark group B (the second position measuringmark 19506 and the second alignment mark 19504). As a result, it ispossible to measure the positions of the mark group A and the mark groupB with respect to the first reference mark and the second referencemark, respectively.

On the other hand, light outgoing from a light source 19514, passesthrough an illumination system 19513, a beam splitter 19512, and a firstimaging system 19520 to be irradiated onto a mark. The reflected lightpasses through the beam splitter 19512 to transmit toward the secondimaging system side. In an image pickup device 19517, the firstreference mark 19509 and the first alignment mark 19503 form an image,thus obtaining a first image. On the other hand, in an image pickupdevice 19519, the second reference mark 19508 and the second alignmentmark 19504 form an image, thus obtaining a second image. The imagepickup devices 19517 and 19519 in this embodiment are a CCD, or thelike.

Next, an alignment method will be described.

First, the pattern forming apparatus of this embodiment is designed sothat a pattern area is imprinted at a desired position in the followingcase during projection of the first position measuring mark 19505 andthe first alignment mark 19503 from the back surface side of the mold ina direction perpendicular to the substrate.

More specifically, in the case when the first alignment mark 19503 andthe second alignment mark 19504 overlap with each other and the firstposition measuring mark 19505 and the second position measuring mark19506 overlap with each other, the pattern forming apparatus is designedso that the pattern area is imprinted at the desired position.

Then, a horizontal/rotational error A (xa, ya, θa) of the secondposition measuring mark 19506 is measured and stored in advance on thebasis of the first position measuring mark 19505. This means that thefirst and second position measuring marks, designed so as to overlapwith each other, are detected as to whether they are actually providedin any positional relationship.

By obtaining the error A (xa, ya, θa), it is found that the imprintingat the desired position can be effected when the alignment of the firstalignment mark 19503 with the second alignment mark 19504 is performedso as to result in an error (B′). This is because, in the case when thefirst and second position measuring marks provided by designing them soas to overlap with each other are actually formed with an error, thefirst alignment mark 19503 located on the same layer as the firstposition measuring mark also includes the error. More specifically, thefirst alignment mark and the first position measuring mark are locatedon the same layer, so that the position of the first alignment mark isensured in a relationship with the first position measuring mark. Here,the term “ensured” means that a designed position and a position of thefirst alignment mark actually formed through the forming process are inagreement with each other with high accuracy.

The alignment of the mold with the work is specifically performed in thefollowing manner.

The first alignment mark 19503 and the second alignment mark 19504 areobserved. FIG. 23B shows an image observed through the image pickup(sensing) device.

As shown in FIG. 23B, on the basis of the first alignment mark 19503, ahorizontal/rotational error B (xb, yb, θb) of the second alignment mark19504 is measured and stored. The resultant positional relationship isequivalent to a positional relationship between the processing patternand the first position measuring mark. The work is moved horizontallyand/or rotationally so that the error B is equal to the error B′,between the first alignment mark and the second alignment mark,calculated from the above-described error A. In other words, thealignment of the mold with the work is effected so as to satisfy thecondition: B=B′. As a result, the processing pattern can be transferredat the desired position.

By the above-described alignment method, even in such a state that themark at the surface of the mold is invisible due to the contact of themold with the resin, the positional relationship between the mark andthe work can be obtained to permit the alignment therebetween.Incidentally, by using the marks at four corner portions, it is possibleto effect magnification correction. Further, depending on referencecoordinates, it is also possible to move the work so that the error B′calculated from the error A (xa, ya, θa) and the measured error B (xb,yb, θb) satisfy the equation: B′+B=0.

Embodiment 5

In this embodiment, a process for producing the mold, different fromthat in Embodiment 3, according to the present invention, is described.

FIGS. 24A to 24E show steps of the mold production process in thisembodiment, wherein processing is effected from one side of the mold. InEmbodiment 3, the processing is effected by turning the mold upsidedown. More specifically, first, one surface of the mold is processed andthen the other surface of the mold is processed. On the other hand, inthis embodiment, both of the front surface and the back surface of themold are processed from the one side direction.

The mold production process of this embodiment will be described withreference to FIGS. 24A to 24G.

More specifically, first of all, a substrate 19601 of a transparentmember is prepared (FIG. 24A). The substrate 19601 has a front surface19602 on which a processing pattern is disposed and a back surface19603.

Next, at the back surface of the substrate, a first position measuringmark 19605 is formed and then on the front surface of the substrate, asecond position measuring mark 19604 is formed (FIG. 24B).

On the same surface as the first position measuring mark 19605, a firstalignment mark (the second mark in the above-described embodiment) islocated and on the same surface as the second position measuring mark19604, a processing pattern alignment mark (the first mark in theembodiment) is located. As a method of successively forming the marks atthe front surface and the back surface from one side of the mold, it ispossible to employ a method using a femtosecond laser having a highaccuracy stage. As a result, the respective marks are disposed ataccurate positions.

Next, a resist 19606 is applied onto the front surface 19602 of thesubstrate 19601 (FIG. 24C). The resist layer 19606 also contains a filmforming material necessary for forming a reflection prevention film, orthe like.

Thereafter, alignment is effected while observing the processing patternalignment mark at the front surface of the substrate, followed by lightexposure and development of a processing pattern (FIG. 24D). For thispurpose, as a light exposure apparatus, it is possible to use anelectron beam exposure device or a light exposure device, such as ascanner or a stepper. These light exposure apparatuses may be suitablyselected depending on a size of the processing pattern.

Next, the substrate is etched, and the resist is removed to complete amold (FIG. 24E).

Incidentally, according to the processing using the femtosecond layer,it is possible to process an inner portion of the mold. Further, in thecase when the processing pattern is on the order of micronanometers, itis also possible to effect the processing by the femtosecond laser inplace of the light exposure apparatus. Further, in the case ofprocessing the inner portion of the mold, it is also possible to employsuch a process that a member is laminated from the front surface side ofthe mold.

Embodiment 6

In this embodiment, a constitutional embodiment using an optical system,different in constitution from that in Embodiment 4, during pressureprocessing using the mold of the present invention, is described.

FIG. 25 is a schematic view for illustrating a constitution of theoptical system without using a reference mark in this embodiment.

In this embodiment, different from Embodiment 4, the optical system doesnot use the reference alignment mark.

More specifically, first, a mold 19701 and a work 19702 are locatedopposite to each other with a certain gap therebetween.

The mold in this embodiment has a first alignment mark 19703 (the secondmark in the embodiment described above), a first position measuring mark19705, and a second position measuring mark 19706 (the first mark in theembodiment). Further, the work has a second alignment mark 19504 (thethird mark in the embodiment).

Next, observation of the first alignment mark 19703 and the secondalignment mark 19704 will be described.

Light outgoing from a light source 19710, passes through an illuminationsystem 19709, and a first imaging system 19707 to be irradiated onto amark. The reflected light passes through the first imaging system 19707and a second imaging system 19711 to be observed through an image pickup(sensing) device 19712. By moving the optical system by means of anoptical system drive mechanism 19713, the first marks (the firstalignment mark and the first position measuring mark) are observed andstored. Then, by moving the optical system, the second marks (the secondalignment mark and the second position measuring mark) are observed andstored.

Next, an alignment method will be described.

First, the first position measuring mark is observed and then the secondposition measuring mark is observed.

From these two images, a horizontal/rotational error A (xa, ya, θa) ofthe second position measuring mark 19506 is measured and stored inadvance on the basis of the first position measuring mark.

Then, the first alignment mark provided on the mold is observed and thenand the second alignment mark provided on the work is observed. FIG. 23Bshows an image observed through the image pickup (sensing) device.

From these two images, on the basis of the first alignment mark, ahorizontal/rotational error B (xb, yb, θb) of the second alignment markis measured and stored. Then, the work is moved horizontally and/orrotationally so that an error B′ between the first alignment mark andthe actually measured error B (xb, yb, θb) satisfy the condition:“B=B′”. As a result, the processing pattern can be transferred at thedesired position.

While the invention has been described with reference to the structuresdisclosed herein, it is not confined to the details set forth and thisapplication is intended to cover such modifications or changes as maycome within the purpose of the improvements or the scope of thefollowing claims.

1-6. (canceled)
 7. A pattern forming method for forming an imprintedpattern on a coating material disposed on a substrate with a patternprovided to a mold, the method comprising: preparing a mold providedwith a first surface including a pattern area, a second surface locatedopposite from the first surface, and an alignment mark provided at aposition at which the alignment mark is away from the first surface;contacting the pattern area of the mold with the coating materialdisposed on the substrate; obtaining information about positions of themold and the substrate by using the alignment mark and a mark providedto the substrate in a state in which the coating material is disposed onthe substrate at a portion where the alignment mark and the substrateare opposite to each other; and effecting alignment of the substratewith the mold in an in-plane direction of the pattern area, on the basisof the information in a state in which the pattern area and the coatingmaterial contact each other.
 8. A method according to claim 7, furthercomprising controlling a distance between the substrate and the mold onthe basis of the information.
 9. A method according to claim 7, furthercomprising curing the coating material while effecting the alignment.10. A method according to claim 7, wherein the coating material is oneof a photocurable resin, a thermosetting resin, and a thermoplasticresin.
 11. A pattern forming method for forming a pattern on a member,to be processed, by using a pattern provided to a mold, the methodcomprising: preparing a mold provided with a first surface including apattern area, a second surface located opposite from the first surface,a first mark provided at the first surface, and a second mark foralignment provided at a position at which the alignment mark is awayfrom the first surface; and effecting alignment of the mold with themember to be processed by using the second mark of the mold and a thirdmark for alignment provided to the member to be processed.
 12. A methodaccording to claim 11, further comprising obtaining information about apositional relationship between the first mark and the second mark andusing the information to effect the alignment of the mold with themember to be processed.
 13. A method according to claim 11, wherein themember to be processed is a substrate or a substrate having a surfacelayer comprising a coating material.
 14. A pattern forming method forforming a pattern on a member, to be processed, by using a patternprovided to a mold, the method comprising: effecting alignment of themold with the member to be processed in an in-plane direction of apattern area of the mold by using first positional information about arelative positional relationship between a first mark provided at asurface of the mold at the same level as a pattern area formed surfaceof the mold and a second mark located away from the pattern area formedsurface and using second positional information about a relativepositional relationship between the second mark and a third markprovided to the member to be processed.
 15. A method according to claim14, wherein the alignment is effected by storing first error informationabout at least one of a horizontal error or a rotational error betweenthe second mark and the first mark, storing second error informationabout at least one of a horizontal error or a rotational error betweenthe second mark and the third mark, and effecting at least one of anoperation for horizontally moving the member to be processed relative tothe mold and an operation for rotationally moving the member to beprocessed relative to the mold.
 16. A pattern forming apparatus forperforming a pattern forming method according to claim 7, the apparatuscomprising: a mold holding portion for holding a mold; and a substratesupporting portion for supporting a substrate, wherein said mold holdingportion and said substrate supporting portion are configured to berelatively moved to each other in an in plane direction.
 17. A patternforming apparatus for performing a pattern forming method according toclaim 11, the apparatus comprising: a mold holding portion for holding amold; and a supporting portion for supporting a member to be processed,wherein said mold holding portion and said supporting portion areconfigured to be relatively moved to each other in an in-planedirection.
 18. An apparatus according to claim 16, wherein said patternforming apparatus further comprises a positional deviation detectionmechanism for detection of the positional deviation between the patternarea of the mold and the coating material in a state of contacttherebetween and a spacing control mechanism for controlling a spacingbetween the substrate and the mold on the basis of detection informationfrom said positional deviation detection mechanism.
 19. A patterntransfer apparatus comprising: an alignment mechanism for effectingalignment of a mold with a member to be processed, said alignmentmechanism being configured to effect alignment of the mold with themember to be processed in an in-plane direction of a pattern area of themold by using first positional information about a relative positionalrelationship between a first mark provided at a surface of the mold atthe same level as a pattern area formed surface of the mold and a secondmark located away from the pattern area formed surface and using secondpositional information about a relative positional relationship betweenthe second mark and a third mark provided to the member to be processed.20. An apparatus according to claim 19, wherein said alignment mechanismcomprises a first storing portion for storing the first positionalinformation and a second storing portion for storing the secondpositional information.